1. Field of the Invention
The present invention relates to speech recognition systems. More particularly, it relates to such a recognitive-word displaying method in a speech recognition system that words being subjects for speech recognition are automatically displayed on a display screen, thereby to assist the user of the system in inputting a voice.
2. Description of the Related Art
FIG. 1 is a block diagram showing the architecture of a prior-art example of a speech recognition system. In the speech recognition system, a microphone 1 receives a voice input and converts it into an electric signal. An analyzer 2 analyzes the inputted voice by the use of, for example, the fast Fourier transform, the linear prediction coefficient analysis, or the like. A feature extractor 3 extracts a feature from the analyzed result of the voice. A word lexicon 4 stores therein reference words which are subjects for speech recognition. A word collator 5 collates the input voice with all the words stored in the word lexicon 4, on the basis of the feature extracted by the feature extractor 3, and it obtains the word which is the most similar to the input voice. A display device 6 displays the recognized result of the word delivered from the word collator 5 and the words stored in the word lexicon 4. Herein, when the display device 6 is to display the words stored in the word lexicon 4, it cannot simultaneously display all the words on a single screen because number of the stored words is large. Therefore, a scroll controller 7 scrolls the words to-be-displayed. A mouse 8 serves to give the scroll controller 7 the command of scrolling the words.
In the word collator 5, the input voice is collated with all the words stored in the word lexicon 4. A technique for the collation is, for example, the DP (Dynamic Programming) matching which is a method for absorbing the lengthening and shortening of the input voice in the temporal direction thereof, or the HMM (Hidden Markov Model) method which utilizes the probability models of word voices. The recognized result, which is the result of the collation, is displayed on the display device 6 as stated above.
The speech recognition system toward which the present invention is directed, is premised on the situation that the user of this speech recognition system does not always know well the reference words being the subjects for recognition. In a case where the speech recognition system is used for inputting, for example, commands, the user does not know the commands well. He/she is therefore permitted to input a specified command in such a way that, while watching commands displayed on the display device 6, he/she enters the specified command as a voice input when the command to be inputted has been displayed.
In the example illustrated in FIG. 1, the user needs to enter a voice input by searching for a command to-be-inputted while scrolling the recognitive subject or reference words, for example, commands indicated on the display screen, by the use of the mouse 8. In this manner, in the prior-art example, the word to be inputted is searched for with the mouse 8, so that when the user has found the particular word on the display screen, he/she can input the specified word, for example, command by clicking this word with the mouse 8. This poses the problem that the necessity of employing the speech recognition is originally questionable.
An object of the present invention is to provide a speech recognition system in which words being subjects for speech recognition are automatically and successively indicated on, for example, a display screen, whereby a word to be entered as a voice input can be readily searched for.
Another object of the present invention is to provide a speech recognition system in which words displayed recently or latest are preferentially indicated, whereby a search time period to find a word to be entered as a voice input can be shortened.
A speech recognition system according to the present invention comprises a recognitive-word storage unit, a speech recognition unit, a display unit, a word storage unit, and a display-word extraction unit.
In the first aspect of the present invention, the recognitive-word storage unit stores therein reference words which are subjects for the recognition of an input voice. The speech recognition unit obtains a word which is the most similar to the inputted voice from among all the recognitive subject words (namely, the reference words being the subjects for recognition) stored in the recognitive-word storage unit, on the basis of the feature of the inputted voice, and it delivers the most similar word as a recognized result. The display unit automatically displays the words stored in the recognitive-word storage unit, in order to assist the user of the speech recognition system in inputting a voice.
In the second aspect of the present invention, the recognitive-word storage unit stores therein reference words which are subjects for the recognition of a current input voice. The speech recognition unit obtains a word which is the most similar to the inputted voice from among all the recognitive subject words stored in the recognitive-word storage unit, on the basis of the feature of the inputted voice, and it delivers the most similar word as a recognized result. The word storage unit stores therein words which may possibly become subjects for the recognition of input voices. The display unit automatically displays the words stored in the word storage unit, in order to assist the user of the speech recognition system in inputting a voice. The display-word extraction unit extracts recently displayed ones of words which have been displayed up to the present by the display unit, as words to become subjects for recognition, and it stores the extracted words in the recognitive-word storage unit.